1. Field of the Invention
The present invention relates to a soil compacting device according to the preamble of patent claim 1.
2. Description of the Related Art
Such a soil compacting device is for example a vibration plate in which a vibration generator, driven by a motor, produces an essentially vertically oriented vibration that loads a compacting plate. Depending on the design of the vibration generator, this generator is also suitable for moving the compacting plate forwards or backwards over the soil to be compacted, and for making the plate steerable.
Such a soil compacting device is known for example from DE 198 40 453 A1. It comprises an extendable undercarriage, so that the device can travel shorter distances on a construction site without requiring a transport vehicle.
In CH-A-321022, a vibration plate is described in which there is attached to the upper mass a pivot mechanism by which an undercarriage can be pivoted between an idle position and a travel position.
In U.S. Pat. No. 3,199,424, a vibration plate is indicated in which an undercarriage is fastened rigidly to a guide rod that is fastened to an upper mass of the vibration plate and that can be pivoted relative thereto.
From DE-U-85 13 149, a vibration plate is known having a lower mass comprising a compacting plate, an upper mass connected with the lower mass via a spring, a vibration generator that loads the compacting plate, and an undercarriage having roller elements situated in rotatable fashion on an undercarriage axle for the transporting of the device, the undercarriage axle being stationary in relation to the device, and the undercarriage being attached to the lower mass.
In addition, vibration plates are known, such as the AVP 2920 of the AMMANN company, in which an undercarriage is provided with a pivot mechanism that can move wheels from a rest position into a travel position. However, the pivot mechanism has an expensive construction, in order to avoid wear on the pivot bearings due to the vibrations that occur.
In the cited vibration plate, the pivot mechanism is fastened to the upper mass or drawbar. In these constructive forms, in contrast, in the travel position the wheels are situated under the compacting plate. Due to the situation of the drawbar and a very large distance of the center of gravity of the overall system from the rotational axle of the wheels, the travel behavior is not very satisfactory. For larger compacting plates in particular, strong holding forces are necessary to prevent the plate from making a tipping movement in the direction of travel about the wheel rotational axle. The installation of the undercarriage in its travel position often presents problems for the user, because in most cases a series of hand grips has to be provided. This entails a risk of injury to the user if the installation is not executed correctly.
The present invention is based on the object of indicating a soil compacting device comprising an undercarriage, in which the above-described disadvantages are avoided.